Tuesday, December 20, 2011

LCD screen harvests light to power devices

AppId is over the quotaAppId is over the quota Summary: Keeping smartphones and laptops charged when there’s no electrical outlet in sight is a perennial challenge. A novel LCD screen developed by UCLA engineers could potentially help solve the problem.

UCLA engineers have developed an LCD screen with built-in photovoltaic polarizers that harvest and recycle energy from ambient light, sunlight, and its own backlight.

The energy-harvesting polarizer, which in technical terms is called a polarizing organic photovoltaic, can potentially boost the function of an LCD by working simultaneously as a polarizer–a photovoltaic device and an ambient light or sunlight photovoltaic panel.

“I believe this is a game-changer invention to improve the efficiency of LCD displays,” said Yang Yang, a professor of materials science at UCLA Engineering and principal investigator on the research. “In addition, these polarizers can also be used as regular solar cells to harvest indoor or outdoor light. So next time you are on the beach, you could charge your iPhone via sunlight.”

LCDs, or liquid crystal displays, shine light through a combination of liquid crystals and polarized glass to produce a visible image, albeit inefficiently. According to the UCLA researchers, a device’s backlight can consume 80 to 90 percent of the device’s power, but as much as 75 percent of the light generated is lost through the polarizers. A polarizing organic photovoltaic LCD could recover much of that lost energy.

Youssry Boutros, program director at Intel Labs, said: “The polarizing organic photovoltaic cell demonstrated by Professor Yang’s research group can potentially harvest 75 percent of the wasted photons from LCD backlight and turn them back into electricity.” Intel supported the research through its Intel Labs Academic Research Office (ARO).

“In the near future, we would like to increase the efficiency of the polarizing organic photovoltaics, and eventually we hope to work with electronic manufacturers to integrate our technology into real products”, Yang said. “We hope this energy-saving LCD will become a mainstream technology in displays.”

Below is a short clip of the UCLA team making the polarizing film using P3HT, an organic polymer widely used in solar cells.

The research is published in the online version of the journal Advanced Materials.